Design of a New Transformer-Isolated Analog Acquisition System

A new transformer-isolated analog acquisition system that is described in this paper greatly reduces the size, weight, and cost of the isolation transformer. This paper also develops the concept of pulsing the isolated analog signal only for the portion of time needed for analog-to-digital conversion. An operational amplifier with a feedback winding from the isolation transformer achieves high accuracy for the isolated analog signal. Other topics in this paper include the additional use of the isolation transformer for an isolated switched-mode power supply and the implementation of the isolation transformer through the use of a small E-E ferrite core and printed-circuit windings.